TY - GEN A1 - Sullivan, J. T. A1 - Wilks, Regan G. A1 - Winkler, M. T. A1 - Weinhardt, Lothar A1 - Recht, D. A1 - Said, A. J. A1 - Newman, B. K. A1 - Zhang, Y. A1 - Blum, Monika A1 - Krause, S. A1 - Yang, Wan Li A1 - Heske, Clemens A1 - Aziz, M. J. A1 - Bär, Marcus A1 - Buonassisi, T. T1 - Soft x-ray emission spectroscopy studies of the electronic structure of silicon supersaturated with sulfur N2 - We apply soft x-ray emission spectroscopy (XES) to measure the electronic structure of crystalline silicon supersaturated with sulfur (up to 0.7 at. %), a candidate intermediate-band solar cell material. Si L2,3 emission features are observed above the conventional Si valence band maximum, with intensity scaling linearly with S concentration. The lineshape of the S-induced features change across the insulator-to-metal transition, indicating a significant modification of the local electronic structure concurrent with the change in macroscopic electronic behavior. The relationship between the Si L2,3 XES spectral features and the anomalously high sub-band gap infrared absorption is discussed. KW - black silicon KW - solar cells KW - electronic surface structure KW - x-ray emission spectroscopy Y1 - 2011 ER - TY - GEN A1 - Weinhardt, Lothar A1 - Benkert, Andreas A1 - Meyer, Frank A1 - Blum, Monika A1 - Wilks, Regan G. A1 - Yang, Wan Li A1 - Bär, Marcus A1 - Reinert, Friedrich A1 - Heske, Clemens T1 - Nuclear dynamics and spectator effects in resonant inelastic soft x-ray scattering of gas-phase water molecules T2 - The journal of chemical physics N2 - The electronic structure of gas-phase H2O and D2O molecules has been investigated using resonant inelastic soft x-ray scattering (RIXS). We observe spectator shifts for all valence orbitals when exciting into the lowest three absorption resonances. Strong changes of the relative valence orbital emission intensities are found when exciting into the different absorption resonances, which can be related to the angular anisotropy of the RIXS process. Furthermore, excitation into the 4a1 resonance leads to nuclear dynamics on the time scale of the RIXS process; we find evidence for vibrational coupling and molecular dissociation in both, the spectator and the participant emission. Y1 - 2012 SN - 1089-7690 VL - 136 IS - 14 SP - 144311 ER - TY - GEN A1 - Bär, Marcus A1 - Klaer, Joachim A1 - Weinhardt, Lothar A1 - Wilks, Regan G. A1 - Krause, Stefan A1 - Blum, Monika A1 - Yang, Wan Li A1 - Heske, Clemens A1 - Schock, Hans-Werner T1 - Cu 2−x S Surface Phases and Their Impact on the Electronic Structure of CuInS 2 Thin Films – A Hidden Parameter in Solar Cell Optimization T2 - Advanced Energy Materials N2 - The surface properties of CuInS 2 (CIS) thin-fi lm solar cell absorbers are investigated by a combination of electron and soft X-ray spectroscopies. Spatially separated regions of varying colors are observed and identifi ed to be dominated by either CuS or Cu 2 S surface phases. After their removal by KCN etching, the samples cannot be distinguished by eye and the CIS surface is found to be Cu-defi cient in both regions. However, a signifi cantly more pronounced off-stoichiometry in the region initially covered by Cu 2 S can be identifi ed. In this region, the resulting surface band gap is also signifi cantly larger than the E g Surf of the initially CuS-terminated region. Such variations may represent a hidden parameter which, if overlooked, induces irreproducibility and thus prevents systematic optimization efforts. Y1 - 2013 SN - 1614-6840 VL - 3 IS - 6 SP - 777 EP - 781 ER -